First, immunology isn’t a completely understood field, it is an area of active research and still being discovered its working mechanism. Keeping that in mind, I’m going to help you understand the concepts of this study.

The conclusion of this study was based on inflammatory response to decompression, which is an indicator of how the organism reacts to bubble formation.

For those without medical knowledge (most of us), you may say that the body treats bubbles as an infection or as a foreign body 1,2.

The Chemokines are used in the study as indicators of a good decompression. Why?

Bubbles on the bloodstream are treated by the organisms as a foreigner body or infection, thus, Chemokines served as indicator of the immune response to an inflation caused by the bubbles.

Their (chemokines) main function is recruiting glucoside- white blood cells out of the bloodstream when an infection is present. From the blood into the interstitial fluid where they can fight the invading pathogen that is causing the inflammatory responses. These Chemokines will interact with receptors at the surface of the glucosides causing adhesion of these cells to the apical membrane of the endothelial cells.

In figure 1, you may observe a blood vessel, the exchange of gases and other nutrients which is at normal state. All blood vessels have the same basic structure. These vessels are designed to transport nutrients and oxygen to the tissues of the body. They also take waste, carbon dioxide, and carry it away from the tissues and back to the heart.

Now on Figure 2, you can observe what will happen when an intruder, a bubble, is present.

Simplifying things, the tissues cells that are in contact with the bubble, start releasing chemicals that are messenger. These are chemokines. Direct contact activates the mast cells, or it could be for chemokines signaling. The mast cells release histamine, one of the main actors and byproduct of the inflammatory process. This’s the first line of defense. So, histamine made the capillaries larger, called dilation. And this made some of the swelling. At this stage, fluid is building up.

Once separated the endothelial cells, the opened wall lets pass the neutrophil and proteins cells that will try to eat the foreign body. The fluid passing throughout the vessel wall is called exuded. And that is why we can watch the macro symptoms at tissue level, which are: redness, swelling, heat and pain.

What could happen with the bubble is that it could became encapsulated it, stopping blood to flow in that area.

I hope this explanation helped you to understand why they used chemokines as an indicator.

Regarding the conclusion of this study, one interesting fact is that applying deep stop procedural into our decompression may not be the best alternative. On my opinion, deep stops should be included in the algorithm and not as external procedure calculation.

Remember that there is a significant difference between algorithms, like the Thalmann algorithm or Bühlmann , which are compartmental algorithms and a procedure, like Ratio Deco. In any case, knowing Ratio is a reliable source of comparison and some procedure could be included in with safety.

At the end, I would say, what is in question is how beneficial and for how long should “deep stop” be performed.

Look, there is evidence that “deep stops” are not beneficial, but there is much to understand yet. But you should know for certainty at what depth you will start off-gassing and if you want to insert a deep stop, it should be at that depth or shallower, no more than 2 minutes in increments of 3 meters.

Carlos Lander

^{2 In immunology, pertaining to substances not recognized as “self” and capable of inducing an immune response.foreign body reaction a granulomatous inflammatory response evoked by the presence of a foreign body in thetissues; a characteristic feature of this is the formation of foreign body giant cells (see giant cell).}

Update

A group from Second Military Medical University in Shanghai led by Weighang Xu, recently published a series of articles describing their studies of how MPs may be related to DCS. Specifically, they studied a subgroup of endothelial microparticles (EMPs). The endothelium is a single cell layer that lines the inner surface of our blood and lymphatic vessels. There are more than a trillion endothelial cells in the body covering 3000 square meters area — they are involved in the control of vasomotor tonus, maintenance of structure and integrity of blood vessels, growth of new blood vessels, maintenance of blood fluidity, repair of tissue damage, regulation of blood clotting and prevention of hemorrhage, initiation and control of inflammation. It was shown previously that diving affects endothelial function and that it may be related to DCS.

In a series of in-vivo and in-vitro studies, Xu and his coworkers demonstrated how contact with bubbles changes endothelial cells and their function, described some of the mechanism and demonstrated how the adverse effects of bubbles may be prevented by various pre-treatments.